three kernel server fixes

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Merge tag 'v6.13-rc3-ksmbd-server-fixes' of git://git.samba.org/ksmbd

Pull smb server fixes from Steve French:

 - Two fixes for better handling maximum outstanding requests

 - Fix simultaneous negotiate protocol race

* tag 'v6.13-rc3-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
  ksmbd: conn lock to serialize smb2 negotiate
  ksmbd: fix broken transfers when exceeding max simultaneous operations
  ksmbd: count all requests in req_running counter

fs/smb/server/connection.c

@@ -70,7 +70,6 @@ struct ksmbd_conn *ksmbd_conn_alloc(void)
 	atomic_set(&conn->req_running, 0);
 	atomic_set(&conn->r_count, 0);
 	atomic_set(&conn->refcnt, 1);
-	atomic_set(&conn->mux_smb_requests, 0);
 	conn->total_credits = 1;
 	conn->outstanding_credits = 0;
 
@@ -120,8 +119,8 @@ void ksmbd_conn_enqueue_request(struct ksmbd_work *work)
 	if (conn->ops->get_cmd_val(work) != SMB2_CANCEL_HE)
 		requests_queue = &conn->requests;
 
+	atomic_inc(&conn->req_running);
 	if (requests_queue) {
-		atomic_inc(&conn->req_running);
 		spin_lock(&conn->request_lock);
 		list_add_tail(&work->request_entry, requests_queue);
 		spin_unlock(&conn->request_lock);
@@ -132,11 +131,14 @@ void ksmbd_conn_try_dequeue_request(struct ksmbd_work *work)
 {
 	struct ksmbd_conn *conn = work->conn;
 
+	atomic_dec(&conn->req_running);
+	if (waitqueue_active(&conn->req_running_q))
+		wake_up(&conn->req_running_q);
+
 	if (list_empty(&work->request_entry) &&
 	    list_empty(&work->async_request_entry))
 		return;
 
-	atomic_dec(&conn->req_running);
 	spin_lock(&conn->request_lock);
 	list_del_init(&work->request_entry);
 	spin_unlock(&conn->request_lock);
@@ -308,7 +310,7 @@ int ksmbd_conn_handler_loop(void *p)
 {
 	struct ksmbd_conn *conn = (struct ksmbd_conn *)p;
 	struct ksmbd_transport *t = conn->transport;
-	unsigned int pdu_size, max_allowed_pdu_size;
+	unsigned int pdu_size, max_allowed_pdu_size, max_req;
 	char hdr_buf[4] = {0,};
 	int size;
 
@@ -318,6 +320,7 @@ int ksmbd_conn_handler_loop(void *p)
 	if (t->ops->prepare && t->ops->prepare(t))
 		goto out;
 
+	max_req = server_conf.max_inflight_req;
 	conn->last_active = jiffies;
 	set_freezable();
 	while (ksmbd_conn_alive(conn)) {
@@ -327,6 +330,13 @@ int ksmbd_conn_handler_loop(void *p)
 		kvfree(conn->request_buf);
 		conn->request_buf = NULL;
 
+recheck:
+		if (atomic_read(&conn->req_running) + 1 > max_req) {
+			wait_event_interruptible(conn->req_running_q,
+				atomic_read(&conn->req_running) < max_req);
+			goto recheck;
+		}
+
 		size = t->ops->read(t, hdr_buf, sizeof(hdr_buf), -1);
 		if (size != sizeof(hdr_buf))
 			break;

fs/smb/server/connection.h

@@ -107,7 +107,6 @@ struct ksmbd_conn {
 	__le16				signing_algorithm;
 	bool				binding;
 	atomic_t			refcnt;
-	atomic_t			mux_smb_requests;
 };
 
 struct ksmbd_conn_ops {

fs/smb/server/server.c

@@ -270,7 +270,6 @@ static void handle_ksmbd_work(struct work_struct *wk)
 
 	ksmbd_conn_try_dequeue_request(work);
 	ksmbd_free_work_struct(work);
-	atomic_dec(&conn->mux_smb_requests);
 	/*
 	 * Checking waitqueue to dropping pending requests on
 	 * disconnection. waitqueue_active is safe because it
@@ -300,11 +299,6 @@ static int queue_ksmbd_work(struct ksmbd_conn *conn)
 	if (err)
 		return 0;
 
-	if (atomic_inc_return(&conn->mux_smb_requests) >= conn->vals->max_credits) {
-		atomic_dec_return(&conn->mux_smb_requests);
-		return -ENOSPC;
-	}
-
 	work = ksmbd_alloc_work_struct();
 	if (!work) {
 		pr_err("allocation for work failed\n");
@@ -367,6 +361,7 @@ static int server_conf_init(void)
 	server_conf.auth_mechs |= KSMBD_AUTH_KRB5 |
 				KSMBD_AUTH_MSKRB5;
 #endif
+	server_conf.max_inflight_req = SMB2_MAX_CREDITS;
 	return 0;
 }
 

fs/smb/server/server.h

@@ -42,6 +42,7 @@ struct ksmbd_server_config {
 	struct smb_sid		domain_sid;
 	unsigned int		auth_mechs;
 	unsigned int		max_connections;
+	unsigned int		max_inflight_req;
 
 	char			*conf[SERVER_CONF_WORK_GROUP + 1];
 	struct task_struct	*dh_task;

fs/smb/server/smb2pdu.c

@@ -1097,6 +1097,7 @@ int smb2_handle_negotiate(struct ksmbd_work *work)
 		return rc;
 	}
 
+	ksmbd_conn_lock(conn);
 	smb2_buf_len = get_rfc1002_len(work->request_buf);
 	smb2_neg_size = offsetof(struct smb2_negotiate_req, Dialects);
 	if (smb2_neg_size > smb2_buf_len) {
@@ -1247,6 +1248,7 @@ int smb2_handle_negotiate(struct ksmbd_work *work)
 	ksmbd_conn_set_need_negotiate(conn);
 
 err_out:
+	ksmbd_conn_unlock(conn);
 	if (rc)
 		rsp->hdr.Status = STATUS_INSUFFICIENT_RESOURCES;
 

fs/smb/server/transport_ipc.c

@@ -319,8 +319,11 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req)
 		init_smb2_max_write_size(req->smb2_max_write);
 	if (req->smb2_max_trans)
 		init_smb2_max_trans_size(req->smb2_max_trans);
-	if (req->smb2_max_credits)
+	if (req->smb2_max_credits) {
 		init_smb2_max_credits(req->smb2_max_credits);
+		server_conf.max_inflight_req =
+			req->smb2_max_credits;
+	}
 	if (req->smbd_max_io_size)
 		init_smbd_max_io_size(req->smbd_max_io_size);